Field of the Invention
The present invention relates to a power transmission apparatus for a vehicle. More particularly, the present invention relates to a power transmission apparatus for a vehicle that realizes eight forward speed stages and one reverse speed stage using two synchronizers and two planetary gear sets.
Description of Related Art
Environmental friendliness of vehicles is very important and survival of future motor industry is dependent on this. Vehicle makers are focusing on development of environmentally-friendly vehicles so as to meet environment and fuel consumption regulations.
Some examples of such environmentally-friendly vehicles include an electric vehicle (EV) and a hybrid electric vehicle (HEV) that use electrical energy, and a double clutch transmission (DCT) that improves efficiency and convenience.
The DCT includes two clutch devices and a gear train of a manual transmission. The DCT selectively transmits torque input from an engine to two input shafts through two clutches, changes the torque selectively transmitted to the two input shafts through the gear train, and outputs the changed torque.
The DCT is used to realize a compact transmission achieving a forward speed stage higher than a fifth forward speed stage. The DCT is used as an automated manual transmission that does not require a driver's manual manipulation by controlling two clutches and synchronizing devices by a controller.
Compared with an automatic transmission with planetary gear sets, the DCT has excellent power delivery efficiency, simplifies change and addition of components for achieving multiple gear stages, and improves fuel economy.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.